Traffic, bandwidth, speed, rate
Set up the network, according to regulations, we need to get a business license issued by the Ministry of Industry. We use the network, provided by the operator. Operator refers to the network operator (providing Internet services organization, also known as ISP), including: Mobile, Telecom, China Netcom, China Railcom, the Great Wall, Tianwei, Education Network, broadcasting, Founder, and so on.
Now, the network operators to provide, for a fee, the reason charges, mainly operators to provide a channel (base station recommendations, etc.), quite close tolls. That is how the specific charge of it?
First is a few concepts: traffic, bandwidth, speed and rate.
(1) Flow
Flow body reflects the amount or volume of information units B, Byte, i.e. bytes.
"The flow of video broadcast reach 300G", referring to 300GB, 300G bytes.
Flow with the file size is similar to the concept, are used to reflect Byte. Flow from the wording of view, emphasizing the body mass during the transmission of information, and the file is stationary relative concept.
Generally operators to traffic or bandwidth (speed) to charge.
Mobile network (radio, 3g, 4g or the like, speed and stability are considered point) by the time the flow rate or charge. We all worry about the phone traffic, because it is to give money.
Bandwidth of the network, i.e. a wired network (200M fiber to the home or the like, wifi uses will also fall into this category), generally based on the bandwidth (speed) basis.
Generally, we say "run traffic", to put a mobile phone traffic, and wifi is not run traffic (using a bandwidth of the network).
Simple to understand, data traffic is file size, is how many bytes mean.
(2) Bandwidth
Bandwidth traffic flow reflects the ability of the channel, the unit is bps, bit per second, that is, bits per second, how many bits can be transmitted per second. For example 200Mbps bandwidth, can transmit one second is 200Mbit. 200Mbps bandwidth theoretical maximum download speed: 200Mbps / 8 = 25MB / s.
Bandwidth is like the width of the road, in theory, the wider the road, the more simultaneous passage of vehicles, can bring higher speeds, and bandwidth of the network bandwidth to charge to the general - the wider the road, the higher the cost .
Bandwidth reflects the ability of the transmission, the actual transmission speed, by the speed represented.
(3) speed
If the operator said: unlimited traffic. Then you should note that the speed limit is not it? You have quite a large volume of traffic can be used, but the pass, however, or require a long time to pass over, that is of no significance.
For wireless networks, consider traffic with speed. For wired network, you need to consider the bandwidth with speed.
Rate reflects the quality of transmission units B / s, i.e. bytes per second. Bps from the B / s, is divided by eight.
(4) rate
Rate is often mentioned concept, also known as the bit rate, the unit is bps, the bandwidth is also the unit.
From the perspective of transmission, the transmission rate indicates how many bits in one second. From the perspective of the player, the code rate indicates how many bits (of audio or video data after continuous compression) playing within 1 second.
"The audio bit rate is 128kbps", said the online play this audio when 1 second to transfer 128kb, in order to smooth playback (without considering the case of the pre-buffer). In short, if I want to play songs 32kbps, that I should reach 32kbps bandwidth; if my bandwidth is 4mbps, that can prop up the video bit rate up is 4mbps.
If the situation does not consider changes in rate, bit rate can be simply calculated from (File Size / time) came out, in turn, know the bit rate with time, you can probably calculate the file size (also known traffic consumption).
Now playing online video in general is how much rate it? You can refer to this screenshot:
Screenshot is a video rate of APP provide a three, you can see, the SD version of the lowest-quality video, the total bit rate (video + audio) to go to 500kbps, while HD go to 1mbps, ultra-clear to go 2mbps, Blu-ray (1080p) go to 4mbps. If your bandwidth is 4mbps, that see the blue a bit reluctantly.
For audio (such as songs), the rate is generally much lower, such as 128kbps generally already very high rate (good quality), and some form of voice amr rate of only 8kbps.
Rate from another angle, reflecting the degree of compression files, code compression rate is high, the quality of the restored relatively good.
Knowing that rate, the bandwidth after these basic concepts, you can make some judgments about some things.
For example, rented a cloud service, providing downstream bandwidth is 1M, if you are used to playing a song, the song rate is 16kbps, while the number of people that online play will explode the bandwidth it? (1024/16)